content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.flowable.internal.operators;
  
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.atomic.*;
  
  import org.reactivestreams.*;
  
  import hu.akarnokd.reactivestreams.extensions.RelaxedSubscriber;
  import io.reactivex.common.RxJavaCommonPlugins;
  import io.reactivex.common.annotations.Nullable;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.common.functions.Function;
  import io.reactivex.common.internal.functions.ObjectHelper;
  import io.reactivex.flowable.*;
  import io.reactivex.flowable.internal.queues.SpscLinkedArrayQueue;
  import io.reactivex.flowable.internal.subscriptions.*;
  import io.reactivex.flowable.internal.utils.BackpressureHelper;
  
  public final class FlowableGroupBy<T, K, V> extends AbstractFlowableWithUpstream<T, GroupedFlowable<K, V>> {
      final Function<? super T, ? extends K> keySelector;
      final Function<? super T, ? extends V> valueSelector;
      final int bufferSize;
      final boolean delayError;
  
      public FlowableGroupBy(Flowable<T> source, Function<? super T, ? extends K> keySelector, Function<? super T, ? extends V> valueSelector, int bufferSize, boolean delayError) {
          super(source);
          this.keySelector = keySelector;
          this.valueSelector = valueSelector;
          this.bufferSize = bufferSize;
          this.delayError = delayError;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super GroupedFlowable<K, V>> s) {
          source.subscribe(new GroupBySubscriber<T, K, V>(s, keySelector, valueSelector, bufferSize, delayError));
      }
  
      public static final class GroupBySubscriber<T, K, V>
      extends BasicIntFusedQueueSubscription<GroupedFlowable<K, V>>
      implements RelaxedSubscriber<T> {
  
          private static final long serialVersionUID = -3688291656102519502L;
  
          final Subscriber<? super GroupedFlowable<K, V>> actual;
          final Function<? super T, ? extends K> keySelector;
          final Function<? super T, ? extends V> valueSelector;
          final int bufferSize;
          final boolean delayError;
          final Map<Object, GroupedUnicast<K, V>> groups;
          final SpscLinkedArrayQueue<GroupedFlowable<K, V>> queue;
  
          static final Object NULL_KEY = new Object();
  
          Subscription s;
  
          final AtomicBoolean cancelled = new AtomicBoolean();
  
          final AtomicLong requested = new AtomicLong();
  
          final AtomicInteger groupCount = new AtomicInteger(1);
  
          Throwable error;
          volatile boolean done;
  
          boolean outputFused;
  
          public GroupBySubscriber(Subscriber<? super GroupedFlowable<K, V>> actual, Function<? super T, ? extends K> keySelector, Function<? super T, ? extends V> valueSelector, int bufferSize, boolean delayError) {
              this.actual = actual;
              this.keySelector = keySelector;
              this.valueSelector = valueSelector;
              this.bufferSize = bufferSize;
              this.delayError = delayError;
              this.groups = new ConcurrentHashMap<Object, GroupedUnicast<K, V>>();
              this.queue = new SpscLinkedArrayQueue<GroupedFlowable<K, V>>(bufferSize);
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              if (SubscriptionHelper.validate(this.s, s)) {
                  this.s = s;
                  actual.onSubscribe(this);
                  s.request(bufferSize);
              }
          }
  
          @Override
          public void onNext(T t) {
              if (done) {
                  return;
              }
  
              final SpscLinkedArrayQueue<GroupedFlowable<K, V>> q = this.queue;
  
              K key;
              try {
                  key = keySelector.apply(t);
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  s.cancel();
                  onError(ex);
                  return;
              }
  
              boolean newGroup = false;
              Object mapKey = key != null ? key : NULL_KEY;
              GroupedUnicast<K, V> group = groups.get(mapKey);
              if (group == null) {
                  // if the main has been cancelled, stop creating groups
                  // and skip this value
                  if (cancelled.get()) {
                      return;
                  }
  
                  group = GroupedUnicast.createWith(key, bufferSize, this, delayError);
                  groups.put(mapKey, group);
  
                  groupCount.getAndIncrement();
  
                  newGroup = true;
              }
  
              V v;
              try {
                  v = ObjectHelper.requireNonNull(valueSelector.apply(t), "The valueSelector returned null");
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  s.cancel();
                  onError(ex);
                  return;
              }
  
              group.onNext(v);
  
              if (newGroup) {
                  q.offer(group);
                  drain();
              }
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  RxJavaCommonPlugins.onError(t);
                  return;
              }
              for (GroupedUnicast<K, V> g : groups.values()) {
                  g.onError(t);
              }
              groups.clear();
  
              error = t;
              done = true;
              drain();
          }
  
          @Override
          public void onComplete() {
              if (!done) {
                  for (GroupedUnicast<K, V> g : groups.values()) {
                      g.onComplete();
                  }
                  groups.clear();
                  done = true;
                  drain();
              }
          }
  
          @Override
          public void request(long n) {
              if (SubscriptionHelper.validate(n)) {
                  BackpressureHelper.add(requested, n);
                  drain();
              }
          }
  
          @Override
          public void cancel() {
              // cancelling the main source means we don't want any more groups
              // but running groups still require new values
              if (cancelled.compareAndSet(false, true)) {
                  if (groupCount.decrementAndGet() == 0) {
                      s.cancel();
                  }
              }
          }
  
          public void cancel(K key) {
              Object mapKey = key != null ? key : NULL_KEY;
              groups.remove(mapKey);
              if (groupCount.decrementAndGet() == 0) {
                  s.cancel();
  
                  if (getAndIncrement() == 0) {
                      queue.clear();
                  }
              }
          }
  
          void drain() {
              if (getAndIncrement() != 0) {
                  return;
              }
  
              if (outputFused) {
                  drainFused();
              } else {
                  drainNormal();
              }
          }
  
          void drainFused() {
              int missed = 1;
  
              final SpscLinkedArrayQueue<GroupedFlowable<K, V>> q = this.queue;
              final Subscriber<? super GroupedFlowable<K, V>> a = this.actual;
  
              for (;;) {
                  if (cancelled.get()) {
                      q.clear();
                      return;
                  }
  
                  boolean d = done;
  
                  if (d && !delayError) {
                      Throwable ex = error;
                      if (ex != null) {
                          q.clear();
                          a.onError(ex);
                          return;
                      }
                  }
  
                  a.onNext(null);
  
                  if (d) {
                      Throwable ex = error;
                      if (ex != null) {
                          a.onError(ex);
                      } else {
                          a.onComplete();
                      }
                      return;
                  }
  
                  missed = addAndGet(-missed);
                  if (missed == 0) {
                      return;
                  }
              }
          }
  
          void drainNormal() {
              int missed = 1;
  
              final SpscLinkedArrayQueue<GroupedFlowable<K, V>> q = this.queue;
              final Subscriber<? super GroupedFlowable<K, V>> a = this.actual;
  
              for (;;) {
  
                  long r = requested.get();
                  long e = 0L;
  
                  while (e != r) {
                      boolean d = done;
  
                      GroupedFlowable<K, V> t = q.poll();
  
                      boolean empty = t == null;
  
                      if (checkTerminated(d, empty, a, q)) {
                          return;
                      }
  
                      if (empty) {
                          break;
                      }
  
                      a.onNext(t);
  
                      e++;
                  }
  
                  if (e == r && checkTerminated(done, q.isEmpty(), a, q)) {
                      return;
                  }
  
                  if (e != 0L) {
                      if (r != Long.MAX_VALUE) {
                          requested.addAndGet(-e);
                      }
                      s.request(e);
                  }
  
                  missed = addAndGet(-missed);
                  if (missed == 0) {
                      break;
                  }
              }
          }
  
          boolean checkTerminated(boolean d, boolean empty, Subscriber<?> a, SpscLinkedArrayQueue<?> q) {
              if (cancelled.get()) {
                  q.clear();
                  return true;
              }
  
              if (delayError) {
                  if (d && empty) {
                      Throwable ex = error;
                      if (ex != null) {
                          a.onError(ex);
                      } else {
                          a.onComplete();
                      }
                      return true;
                  }
              } else {
                  if (d) {
                      Throwable ex = error;
                      if (ex != null) {
                          q.clear();
                          a.onError(ex);
                          return true;
                      } else if (empty) {
                          a.onComplete();
                          return true;
                      }
                  }
              }
  
              return false;
          }
  
          @Override
          public int requestFusion(int mode) {
              if ((mode & ASYNC) != 0) {
                  outputFused = true;
                  return ASYNC;
              }
              return NONE;
          }
  
          @Nullable
          @Override
          public GroupedFlowable<K, V> poll() {
              return queue.poll();
          }
  
          @Override
          public void clear() {
              queue.clear();
          }
  
          @Override
          public boolean isEmpty() {
              return queue.isEmpty();
          }
      }
  
      static final class GroupedUnicast<K, T> extends GroupedFlowable<K, T> {
  
          final State<T, K> state;
  
          public static <T, K> GroupedUnicast<K, T> createWith(K key, int bufferSize, GroupBySubscriber<?, K, T> parent, boolean delayError) {
              State<T, K> state = new State<T, K>(bufferSize, parent, key, delayError);
              return new GroupedUnicast<K, T>(key, state);
          }
  
          protected GroupedUnicast(K key, State<T, K> state) {
              super(key);
              this.state = state;
          }
  
          @Override
          protected void subscribeActual(Subscriber<? super T> s) {
              state.subscribe(s);
          }
  
          public void onNext(T t) {
              state.onNext(t);
          }
  
          public void onError(Throwable e) {
              state.onError(e);
          }
  
          public void onComplete() {
              state.onComplete();
          }
      }
  
      static final class State<T, K> extends BasicIntFusedQueueSubscription<T> implements Publisher<T> {
  
          private static final long serialVersionUID = -3852313036005250360L;
  
          final K key;
          final SpscLinkedArrayQueue<T> queue;
          final GroupBySubscriber<?, K, T> parent;
          final boolean delayError;
  
          final AtomicLong requested = new AtomicLong();
  
          volatile boolean done;
          Throwable error;
  
          final AtomicBoolean cancelled = new AtomicBoolean();
  
          final AtomicReference<Subscriber<? super T>> actual = new AtomicReference<Subscriber<? super T>>();
  
          final AtomicBoolean once = new AtomicBoolean();
  
          boolean outputFused;
  
          int produced;
  
          State(int bufferSize, GroupBySubscriber<?, K, T> parent, K key, boolean delayError) {
              this.queue = new SpscLinkedArrayQueue<T>(bufferSize);
              this.parent = parent;
              this.key = key;
              this.delayError = delayError;
          }
  
          @Override
          public void request(long n) {
              if (SubscriptionHelper.validate(n)) {
                  BackpressureHelper.add(requested, n);
                  drain();
              }
          }
  
          @Override
          public void cancel() {
              if (cancelled.compareAndSet(false, true)) {
                  parent.cancel(key);
              }
          }
  
          @Override
          public void subscribe(Subscriber<? super T> s) {
              if (once.compareAndSet(false, true)) {
                  s.onSubscribe(this);
                  actual.lazySet(s);
                  drain();
              } else {
                  EmptySubscription.error(new IllegalStateException("Only one Subscriber allowed!"), s);
              }
          }
  
          public void onNext(T t) {
              queue.offer(t);
              drain();
          }
  
          public void onError(Throwable e) {
              error = e;
              done = true;
              drain();
          }
  
          public void onComplete() {
              done = true;
              drain();
          }
  
          void drain() {
              if (getAndIncrement() != 0) {
                  return;
              }
              if (outputFused) {
                  drainFused();
              } else {
                  drainNormal();
              }
          }
  
          void drainFused() {
              int missed = 1;
  
              final SpscLinkedArrayQueue<T> q = this.queue;
              Subscriber<? super T> a = this.actual.get();
  
              for (;;) {
                  if (a != null) {
                      if (cancelled.get()) {
                          q.clear();
                          return;
                      }
  
                      boolean d = done;
  
                      if (d && !delayError) {
                          Throwable ex = error;
                          if (ex != null) {
                              q.clear();
                              a.onError(ex);
                              return;
                          }
                      }
  
                      a.onNext(null);
  
                      if (d) {
                          Throwable ex = error;
                          if (ex != null) {
                              a.onError(ex);
                          } else {
                              a.onComplete();
                          }
                          return;
                      }
                  }
  
                  missed = addAndGet(-missed);
                  if (missed == 0) {
                      return;
                  }
  
                  if (a == null) {
                      a = this.actual.get();
                  }
              }
          }
  
          void drainNormal() {
              int missed = 1;
  
              final SpscLinkedArrayQueue<T> q = queue;
              final boolean delayError = this.delayError;
              Subscriber<? super T> a = actual.get();
              for (;;) {
                  if (a != null) {
                      long r = requested.get();
                      long e = 0;
  
                      while (e != r) {
                          boolean d = done;
                          T v = q.poll();
                          boolean empty = v == null;
  
                          if (checkTerminated(d, empty, a, delayError)) {
                              return;
                          }
  
                          if (empty) {
                              break;
                          }
  
                          a.onNext(v);
  
                          e++;
                      }
  
                      if (e == r && checkTerminated(done, q.isEmpty(), a, delayError)) {
                          return;
                      }
  
                      if (e != 0L) {
                          if (r != Long.MAX_VALUE) {
                              requested.addAndGet(-e);
                          }
                          parent.s.request(e);
                      }
                  }
  
                  missed = addAndGet(-missed);
                  if (missed == 0) {
                      break;
                  }
                  if (a == null) {
                      a = actual.get();
                  }
              }
          }
  
          boolean checkTerminated(boolean d, boolean empty, Subscriber<? super T> a, boolean delayError) {
              if (cancelled.get()) {
                  queue.clear();
                  return true;
              }
  
              if (d) {
                  if (delayError) {
                      if (empty) {
                          Throwable e = error;
                          if (e != null) {
                              a.onError(e);
                          } else {
                              a.onComplete();
                          }
                          return true;
                      }
                  } else {
                      Throwable e = error;
                      if (e != null) {
                          queue.clear();
                          a.onError(e);
                          return true;
                      } else
                      if (empty) {
                          a.onComplete();
                          return true;
                      }
                  }
              }
  
              return false;
          }
  
          @Override
          public int requestFusion(int mode) {
              if ((mode & ASYNC) != 0) {
                  outputFused = true;
                  return ASYNC;
              }
              return NONE;
          }
  
          @Nullable
          @Override
          public T poll() {
              T v = queue.poll();
              if (v != null) {
                  produced++;
                  return v;
              }
              int p = produced;
              if (p != 0) {
                  produced = 0;
                  parent.s.request(p);
              }
              return null;
          }
  
          @Override
          public boolean isEmpty() {
              return queue.isEmpty();
          }
  
          @Override
          public void clear() {
              queue.clear();
          }
      }
  }
  